On Last One Out...Turn Out the Lights in Halo: Reach, you will be able to earn the I Didn't Train To Be A Pilot achievement which requires you to at least be on Normal difficulty and you have to destroy three of the anti-aircraft batteries. If you're hunting around for a straggler or have NO idea how to do this achievement, check out this video! You will get all the locations of the various anti-air batteries and be set for a cool 10Gs!